Our invention relates to an apparatus for data transfer with a flexible magnetic disk contained in a protective envelope to make up a magnetic disk cartridge, and more specifically to such an apparatus of the type having a pair of magnetic transducer heads for data transfer contact with the opposite faces of a magnetic disk. The data transfer apparatus of our invention is particularly well suited for use with magnetic disks of the class known as "microfloppy disks", which are housed in relatively rigid envelopes having openable shutters to expose parts of the enclosed disks.
The "microfloppy disks" have been known and used extensively which have magnetic disks with diameters of 76 or 86 millimeters rotatably housed in relatively rigid envelopes. The disk cartridges of this class find use with data transfer apparatus, commonly referred to as disk drives or files, having a movable cartridge cradle for receiving a disk cartridge therein. The cartridge cradle travels between a retracted position where the disk cartridge is to be loaded on and unloaded from the cradle, and a working position where the loaded disk cartridge has its disk revolved for processing signals by transducing operation with a magnetic head or heads. Normally locked in the retracted position, the cartridge cradle becomes unlocked upon insertion of the disk cartridge therein and automatically travels with the loaded disk cartridge to the working position.
As heretofore constructed, the cradle locking mechanism has been composed of a locking lever and a pin engageable in a recess in the locking lever. The locking lever is sprung into engagement with the pin to normally hold the cartridge cradle in the retracted position. We object to this known locking mechanism as the locking lever is easy to disengage the pin owing to shocks or vibrations that may be exerted on the apparatus during, for example, its transportation. Such accidental tripping of the locking mechanism presents a problem particularly in conjunction with apparatus of the type having a pair of magnetic transducer heads arranged opposite each other for data transducing contact with the opposite faces of the magnetic disk. The tripping of the locking mechanism when no disk cartridge is loaded in the apparatus has so far resulted directly in the collision of the magnetic heads and, possibly, in their destruction.